Apparatus, systems, and methods for economized vapor compression cycle

ABSTRACT

Apparatus and methods for using said apparatus are described in connection with economized vapor compression heat transfer systems. Working fluid is extracted from a sub-cooler disposed prior to a system evaporator and distributed to the inter-scroll pockets of a compressor via an injection plenum and multiple injection ports for the purpose of increasing Δh across the system to increase its effective heat transfer capacity, thereby providing greater operating efficiency and performance. Further, greater configurability is enabled while manufacturing complexity and cost are reduced.

RELATED APPLICATIONS

This application claims domestic benefit of U.S. Provisional Application No. 62/639,808 entitled “APPARATUS AND METHODS FOR ECONOMIZED VAPOR COMPRESSION CYCLE” and filed on Mar. 7, 2018. Applicant expressly incorporates all portions of said provisional application (62/639,808), along with co-owned U.S. application Ser. No. 12/015,599 (now U.S. Pat. No. 7,963,753) and Ser. No. 14/801,233 (now U.S. Pat. No. 9,856,874), herein by reference in their entirety and for all useful purposes. In the event of inconsistency between anything stated in this specification and anything incorporated by reference in this specification, this specification shall govern.

TECHNICAL FIELD

This invention generally pertains to the design, construction, and methods of use of an apparatus capable of functioning in an economized vapor compression heat transfer system. More specifically, said apparatus comprises a scroll compressor with certain design elements that provide increased compression capacity for a given physical displacement while enabling simplified fabrication methods and a greater degree of configurability than previously achieved in the art. The foregoing description is not limiting upon the disclosure that follows as other uses and benefits of certain novel elements of Applicants' invention will be realized by persons of ordinary skill in the art.

COPYRIGHT STATEMENT

This patent document contains material subject to copyright protection. The copyright owner consents to the storage and reproduction of the instant disclosure in exactly the form it appears in the Patent and Trademark Office records for all purposes associated with the instant application and patent. However, Applicant, its agents, and assigns reserve all copyright rights to this original work for any and all other purposes, particularly but not limited to such rights prohibiting appropriation of the original material herein for unauthorized use by other parties for any purpose. To the extent that any material herein may legitimately fall within the scope of any copyright protection previously claimed by another party, including material presented herein believed subject to the “Fair Use” doctrine, Applicant disclaims any intellectual property ownership thereof or copyright protection therefore.

BACKGROUND

Vapor compression systems are well-known in the art. A working fluid circulated in a closed-loop system by a compressor driven by a source of power, including but not limited to an electric motor, may comprise a system by which heat energy is effectively transferred from a first heat exchanger in a first location to a second heat exchanger in a second location. For example, a conventional refrigeration system may comprise a heat exchanger evaporator in the form of refrigeration coils disposed inside a closed area that are configured to absorb heat energy from said area via a circulating liquid working fluid at relatively low pressure. One or more fans may be used to provide airflow across said refrigeration coils to increase the heat transfer between heated air within the closed area and the working fluid. The pressure of this heated working fluid is then generally increased via one or more working fluid compressors to produce a high temperature and high pressure working fluid vapor with correspondingly high enthalpy, which in turn is supplied to one or more heat exchanger condensers disposed away from the area to be cooled. One or more fans may also be deployed to increase the rate at which this undesired waste heat removed from the working fluid at essentially constant pressure via radiation, convection, or conduction from the condenser(s). Following this heat transfer, the reduced temperature working fluid is expanded, usually via one or more expansion valves, to restore the working fluid to liquid form which is supplied to the evaporator coils to repeat the cycle.

The same process, with slightly reconfigured heat exchangers, may be utilized to provide heat instead of cooling to a desired location. In those systems, the heat exchanger condenser or its associated airflow is located within the area to be heated (such as a building) and the heat exchanger evaporator or its associated airflow is located away from the heated location (such as outside the building).

Although the vapor compression process will generally be described herein as a refrigeration system, use of the disclosed apparatus and methods is intended to apply equally to systems that are capable of providing refrigeration, heating, or both at separate times without limitation. In vapor compression refrigeration systems, heat transfer may be provided by any viable means of thermal communications, including but not limited to conduction, convection, or conduction/advection via air, liquids such as water, working fluid, or compounds such as ethylene glycol specifically formulated for heat transfer, or by use any other desired fluid. Any one or combination of these means may be employed in association with any or all of the system heat exchangers without limitation. While any specific system may be primarily intended to provide either heating or refrigeration, a secondary benefit may be realized by utilizing the corresponding by-product (refrigeration or heating, respectively) for a complementary purpose. For example, and without limitation, waste heat removed from a system working fluid may be used to warm fluids or components in the primary or auxiliary systems operating at less-than-optimal temperatures.

Depending upon the particular application, vapor compression systems may utilize a variety of different types of compressors. Scroll compressors are known in the art to be particularly suitable for use in vapor compression refrigeration systems. This well-known geometry is characterized by a first scroll assembly and a second scroll assembly, each with wrap walls disposed perpendicular to their respective bases and oriented with the wraps intermeshed so as to create one or more regions between the scroll wraps referred to as “pockets”. One wrap is stationary and is referred to herein as the “fixed scroll” while the other scroll, referred to herein as the “orbiting scroll”, is driven about its center of rotation by a motive force typically provided by an electric motor such that the decreasing volume of the pocket(s) between the intermeshed scroll wraps cause a fluid injected into said pockets between the scroll wraps to be compressed and expelled from the compressor at an output pressure greater than that of the input pressure. See, for example, co-owned U.S. application Ser. No. 12/015,599 (now U.S. Pat. No. 7,963,753) and Ser. No. 14/801,233 (now U.S. Pat. No. 9,856,874), both previously incorporated herein by reference, for additional disclosure of exemplary embodiments of scroll compressor geometries pertinent to Applicants' improved designs.

Many operational improvements to scroll compressors deployed in vapor compression refrigeration systems have been developed. For example, U.S. Pat. No. 6,619,936 by Perevozchikov teaches a scroll compressor apparatus and associated method of providing vapor injection at an intermediate pressure to a vapor injection passage, in the form of a single cross-drilled feed hole, extending generally horizontally through the end plate of the non-orbiting scroll member from an exterior position in a radial direction perpendicular to the surfaces of the scroll wraps. Said feed hole vapor passage communicates with a vapor injection port extending generally vertically from that passage through the fixed scroll plate and opens into pockets formed by wraps of the fixed and orbiting scrolls (col. 4 at I. 43-55; see also FIG. 1 herein). Note that the geometry of the vapor injection passage of this embodiment restrict the location of any injection port(s) to an azimuth arc ranging from approximately 270° to 290° from the center of the scroll. It would not be possible to provide any injection ports within the continuous arc ranging clockwise from approximately 290° to approximately 270° without first providing one or more drilled vapor injection passage holes within that arc.

Similarly, U.S. Pat. No. 7,771,178 also by Perevozchikov et al., depicts the use of more than one vapor injection passage comprising a first part extending radially into the non-orbiting scroll end plate and a second portion intersecting the first portion through the end plate, permitting vapor communication from the first portion of the passage to the scroll pockets (col. 3, I. 12-28; also see FIG. 2 herein). Note that in this embodiment, all injection ports must be provided within the azimuthal arc beginning at approximately 170° and continuing clockwise through approximately 10°. No injection ports could be provided anywhere within the azimuthal arc from approximately 10° clockwise through approximately 170°. Note further that at any given azimuth within the arc from approximately 170° through approximately 10°, the permissible radial distance from the center of the scroll for injection port location is severely limited to only the particular distances that are coincident with the linear vapor passage holes. With this geometry, it would be difficult if not impossible to place several injection ports along a curved locus at a given radial distance since such an arc would be largely transverse to the linear vapor passage(s) and therefore not sufficiently aligned for vapor communication.

The purpose of these vapor passages is to provide a means to communicate partially cooled working fluid at an intermediate pressure to the volume between the fixed and orbiting scrolls of the compressor for the purpose of optimizing operation. Specifically, and with reference to FIGS. 3 and 4 herein, injection of a quantity of intermediate pressure working fluid extracted from a flash tank or heat exchanger disposed between a pair of expansion valves configured to establish such preferred value of intermediate pressure provides working fluid at said intermediate pressure to the compressor to provide a greater net change in enthalpy across the system. This effect serves to increase the capacity of a compressor of certain geometry and thereby provide superior performance. This technique is known in the art as “economization”, largely because it enables vapor compression refrigeration systems to achieve greater capacity at a lower cost than can be achieved by increasing compressor displacement and consuming more power to drive the larger compressor.

The operation of a vapor compression refrigeration system is limited by a number of factors, including the efficiency and performance of the system's condenser, evaporator, and compressor. In particular, only a certain pressure differential may be achieved across a compressor of given displacement and configuration, and the amount of heat consumed and rejected by the evaporator and condenser, respectively, are limited by their respective geometries and (in refrigeration mode) the difference between the desired cooling temperature and the ambient temperature to which the condenser is subjected. The difference between the suction and discharge pressures of a particular compressor is limited for a given displacement and this establishes a maximum working fluid mass flow beyond which no further increases in performance are possible via manipulation of compressor parameters. The only way to bolster capacity in this regard would be to substitute a larger compressor with a correspondingly larger source of driving power, thereby increasing the physical size, cost of acquisition, and cost of operation of the system. However, further improvement in system capacity may be achieved via economization techniques discussed in detail below.

Each of the nodes in the economized closed-loop working fluid circuit depicted in FIG. 4 corresponds to an identically-numbered point on the graph of system pressure (P) versus enthalpy (h) shown as FIG. 3. Compressor 401 receives a flow of vaporized working fluid at point 1 from evaporator 406 and compresses said vapor to a maximum system pressure and enthalpy depicted by point 4 at the compressor output. However, within the compressor, the introduction of intermediate pressure working fluid via injection valve 407 reduces the enthalpy of the working fluid during compression (from point 2 to point 3) such that its enthalpy is lower upon exiting the compressor than would otherwise be achieved at the identical pressure of point 4 without economization. Condenser 402 decreases the enthalpy of the working fluid via cooling at an essentially constant pressure, in some cases restoring the working fluid to at least partial liquid phase at point 5. First expansion valve 403 then reduces the pressure of the working fluid to an intermediate pressure at point 6 before communicating the working fluid to flash tank or heat exchanger 404, wherein its enthalpy is further reduced via sub-cooling and vapor/liquid separation at an essentially constant pressure. In some embodiments not depicted, a heat exchanger may be used in lieu of a flash tank to provide the same functionality and serve the same purpose. A certain mass flow of this partially cooled working fluid is extracted at point 9, which shares an essentially common pressure with points 2, 3, 6, and 7; as this pressure is set at a predetermined level between the lowest system pressures at points 1 and 8 and the highest system pressure at points 4 and 5, this is typically referred to as an intermediate pressure. The balance of system working fluid, comprising the largest portion thereof in a predominately liquid state, is extracted from flash tank or heat exchanger 404 at point 7 and allowed to expand at an essentially constant enthalpy via second expansion valve 405, at which point the liquid working fluid at point 8 is once again communicated to evaporator 406 to consume heat energy prior to recompression.

The capacity of a vapor refrigeration system is limited by the change in enthalpy across the system, referred to as Δh, determined by the difference between the highest and lowest system enthalpies across the evaporator (corresponding to points 1 and 8, respectively, in FIG. 3). This is the effective heat transfer limitation of the system which translates directly into the maximum system cooling capacity for any given compressor. Therefore, the economic and operational value of economized vapor compressions systems has been established in the known art as a preferred method for many applications.

However, specialized compressor hardware required by economized systems must overcome certain restrictive limitations. Currently available products fabricated in accordance with present technology are limited in their capacity and by manufacturing limitations. Due to the displacement required for larger capacity systems and their inherent reliability, scroll compressors are often preferred for large capacity vapor compression systems. As discussed above, known configurations of scroll compressors such as those depicted in FIGS. 1 and 2 require a vapor passage to be drilled or formed by casting that runs parallel to the end plate of the fixed scroll, terminating in a port that must be drilled or otherwise formed through said endplate to permit the injected working fluid to pass into the scroll compressor pockets. This imposes additional manufacturing burdens, as each fixed scroll unit must either have the long passages parallel to the end plate individually drilled or be separately cast as shown below.

FIG. 5 presents the outside terminations 501 and 502 of vapor passages consistent with the prior art scroll compressors of FIGS. 1 and 2. These passages terminate in one or more intersecting vapor ports 601 and 602 drilled perpendicularly through the scroll end plate as shown in FIG. 6 from the underside. As the placement of the ports is critical to the design and operation of the compressor (discussed fully below), the angle and depth of the passages is critical and must be machined within exacting tolerances. The additional skilled labor required of manufacturers to configure every scroll via additional machining in this manner adds to the production time and cost of the units. Further, depending on the requirements of each particular compressor, different configurations may be required with each one requiring considerable additional fabrication.

In lieu of individually configuring each end plate with drilled vapor passages and intersecting ports, some prior art compressor manufacturers provide scroll compressors with end plates with passages embedded in the casting. FIG. 7A depicts one such component similar to that taught by Bush et al. (see U.S. Pat. No. 6,142,753) and Lifson (see U.S. Pat. No. 7,100,386).; a “V” shaped passage 701 is embedded in the outside face of end plate configured to provide working fluid to two elongated ports, 702 and 703, on opposite sides of the scroll. The outline of a gasket and cover for the channel can be seen on the face of the plate. FIG. 7B shows the elongated holes on the scroll side (inside) of the same assembly. As evidenced by the elongated holes, this cast assembly provides no flexibility for placement of the ports during the manufacturing process to accommodate variations in design and operation, including the volume of the channel passage, the placement of the ports, or the cross-sectional area of the ports. The major axes of the elongated ports shown in the patent drawings and in the physical manifestation of the design is seen to not be parallel to the direction of the channels. New or modified castings may be required and fabricated for each particular compressor configuration because elongated holes cannot be easily drilled subsequent to casting.

These prior art vapor compression configurations have also proven to be inadequate for use in large displacement compressors primarily due to inherent limitations in their designs. In the case of the compressors with drilled passages, all of the ports must be located along the straight drilled passage. As will be discussed further below, the inherent curvature of the scrolls does not lend itself to the use of such straight passages. In the case of cast passages, port placement and configuration is problematic and practicable large capacity compressors have not yet been fabricated using this technique.

What is needed is an improved compressor design for economized systems that eliminates the need for excessive specialized processing of scroll components and that also provides a high degree of configuration flexibility so that production time and costs are reduced. Applicants have invented a scroll compressor design that facilitates improved configurability with lower manufacturing costs and has proven to be capable of operation in large displacement compressors.

BRIEF DESCRIPTION OF SOME ASPECTS OF THE INVENTION

Applicants have invented apparatus and methods for using said apparatus in connection with economized vapor compression heat transfer systems. Working fluid is extracted from a sub-cooler disposed prior to a system evaporator and distributed to the inter-scroll pockets of a compressor via an injection plenum and multiple injection ports for the purpose of increasing Δh across the system to increase its effective heat transfer capacity, thereby providing greater operating efficiency and performance. Further, greater configurability is enabled while manufacturing complexity and cost are reduced.

The invention disclosed and claimed herein comprises an improvement to a scroll compressor apparatus more fully described in co-owned U.S. application Ser. No. 12/015,599 (now U.S. Pat. No. 7,963,753) and Ser. No. 14/801,233 (now U.S. Pat. No. 9,856,874) previously incorporated herein by reference in its entirety and for all useful purposes. The instant disclosure is properly focused on the aspects and embodiments of the improvement without limiting Applicants' reliance on all of said incorporated material as though it was directly recited herein. Although Applicants' disclosure is presented with respect to certain embodiments of its own scroll compressor design, it would be immediately apparent to a person of ordinary skill in the art that the novel elements of this invention as disclosed may be utilized with scroll compressors of different designs. In other words, not every element of Applicants' particular scroll compressor may be necessary to practice the novel embodiments disclosed herein and said disclosure covers all such embodiments.

In lieu of the economizer vapor passages in the known art discussed above with respect to FIGS. 1-7, and as supported by the drawings and further written description that comprise the whole of the disclosure of this invention, certain embodiments of the inventive apparatus comprises a circumferential injection plenum separated from the fixed scroll wraps by a planar base structure with one or more injection ports disposed through said planar base to permit pressurized working fluid to pass from the plenum on one face of said planar base into the pockets of the scroll on the opposite face of said planar base, said pockets defined as the spaces between the walls of the fixed and orbiting scrolls, at points of equal pressure and at the optimal time during the rotation of the orbiting scroll with respect to the position of the fixed scroll. The injection plenum in one embodiment comprises at least one machined channel in the planar surface of the fixed scroll further comprising one or more injection port(s), at least one sealing gasket, and at least one injection plenum sealing plate that in combination describe a ported volume into which intermediate pressure working fluid is received from the system and injected into the scroll.

In one embodiment, the injection plenum comprises a volume with one or more vapor input(s) and is configured such that one or more vapor injection ports may be provided at any desired azimuth angle around the periphery of the fixed scroll base and within a discrete but continuous range of radial distances. The term “circumferential ” is used in this disclosure to describe the injection plenum of this embodiment wherein injection ports may be positioned at any azimuth around the entire circumference of the fixed scroll base. Though “circumferential” usually brings to mind a circular shape, Applicants' use of the term is not limited only to circular injections plenums. Whereas the longitudinal vapor channels of the prior art described above enable placement of injection ports only within certain arcs of azimuth that include the longitudinal vapor channels and at azimuth-dependent radial distances that coincide with the longitudinal vapor channels, Applicants' novel system permits injection ports to be located around the entire periphery of the scroll at azimuth-independent radial distances. Since the circumferential injection plenum of this embodiment comprises a volume with a permissible radial displacement independent of azimuth, this invention permits injection ports to be provided at any azimuth at any radial distances from the center of scroll within discrete limits but continuous within that range. This feature solves the problem of the prior art geometries discussed above, and in greater detail below, of conforming the location of adjacent injection ports to the curved walls of the scroll wrap with linear vapor passages. Applicant's system permits multiple adjacent injection ports to be provided at the same or different radial distances from the center of the scroll at any desired azimuth so that they conform exactly to the scroll wrap walls that are similarly disposed.

In some embodiments, a floating seal plate is disposed atop said plenum and within a back chamber between an outer enclosure and the surface of the floating seal plate opposite the plenum. This back chamber is pressurized via an intermediate pressure tap from a pocket within the scroll at a higher pressure than that present within the injection plenum. As the pressure of the working fluid supplied to the back chamber via the intermediate pressure tap is greater than the pressure of the working fluid injected via the injection ports, the floating seal plate is constrained in the proper position against the surface of the scroll by said pressure, thereby providing a stabilizing force and maintaining axial compliance of the orbiting scroll below. The use of a pressure-restrained seal plate obviates the need for mechanically-fastened means of supporting the orbiting scroll and minimizes the attendant transmission of disruptive mechanical vibrations from the compressor structure. In addition to this beneficial shock absorption, the floating seal plate provides the necessary stabilization to the orbiting scroll while imposing minimum rotational frictional force that causes wear and increases the likelihood of mechanical failure.

Applicants' economizer injection plenum as taught and shown in the accompanying drawings is enabling without limitation upon the precise physical geometry of any equivalently-functional economizer injection plenum. For example, a person of ordinary skill in the art will appreciate that this disclosure enables the use of a volume of any other shape disposed in such a manner to enable direct communication of intermediate pressure working fluid into the wraps of a scroll compressor via one or more injection ports located within the extent of a two dimensional area that is not necessarily circular as described in the written description and drawings. This novel element of Applicants' invention stands in stark contrast to the known use of injection port(s) restricted to the locus of points defined by a single straight (one-dimensional) vapor passage. Similarly, the teaching of a gasket to provide an effective seal between surfaces defining Applicants' injection plenum of the embodiments herein may comprise any flat, curved, O-ring, or other gasket types and configurations that may be effective for the intended purpose in conjunction with a plenum of a different configuration. A person of ordinary skill in the art will immediately recognize that the instant disclosure teaches the use of a novel three-dimensional plenum that is (a) easily distinguishable from the linear vapor passage channels previously known, (b) that comprises a significantly larger cross-sectional area to enable injection port placement with much greater flexibility and versatility, and (c) that said geometry overcomes multiple limitations with the known art, both operational and in component fabrication.

Similarly, Applicants' disclosure of a floating seal plate retained in position within a back chamber pressurized via an intermediate pressure tap is not limited to the specific elements depicted in the drawings, as a person of ordinary skill in the art will appreciate that any number of equivalent sources of pressurized working fluid within the system (including the compressor output) may also be used to achieve the same results.

The scroll architecture comprising an injection plenum of the apparatus disclosed herein offers numerous advantages over the systems known in the art. Instead of requiring vapor passages to be individually drilled through the fixed scroll end plate with depths, diameters, and angles specifically compatible with injection port locations specific to each unique compressor configuration, any number of injection ports may be placed in any location within the circumference of the injection plenum and at any desired radial distance(s) from the center of the scroll. When a straight vapor passage is provided, as in the prior art, all of the intersecting injection ports are constrained to an essentially straight line along that vapor passage. Since a scroll compressor is inherently a curved structure, and for reason discussed below and in the accompanying drawings, selecting optimal port locations may not be feasible in practice with the methods presently known in the art. However, when injection port location is restricted only to any point disposed within an injection plenum, an infinite number of linear or non-linear possibilities exist. Further, multiple compressor designs may be easily accommodated without the need to drill specialized vapor passages, instead drilling only the injection ports in their desired locations.

In one embodiment of the invention, intermediate pressure working fluid recovered from the system is communicated to at least one scroll economizer port which in turn communicates said working fluid through a series of one or more vapor passages internal to the upper fixed scroll to the injection plenum. This embodiment is suitable for smaller compressor capacities and displacements where sufficient material exists within the structure of the scroll to accommodate vapor passages capable of communicating the required mass flow rate at the appropriate pressure.

Larger capacity compressors will require higher mass flow rates and correspondingly larger cross-sectional vapor passages leading to the injection plenum. In some embodiments, the required cross-sectional area may be greater than can be safely accommodated by the physical structure of the scroll apparatus In one embodiment of the invention, intermediate pressure working fluid recovered from the system is communicated to at least one scroll economizer port which in turn communicates said working fluid to the injection plenum via one or more conduits or tubes external to the structure of the compressor in lieu of internal vapor passages. This embodiment is suitable for larger compressor capacities and displacements where insufficient volume is available within the structure of the scroll to accommodate the necessary mass flow rate or where additional cross-sectional area is necessary to achieve higher system capacities. By increasing the number of conduits or tubes, their diameter(s), or both, any practicable mass flow of vapor may be delivered to the injection plenum at the desired pressure.

The use of external vapor conduits to supply the injection plenum with intermediate pressure working fluid enable the apparatus of this invention to provide economized operation at significantly greater capacities than is possible using the drilled or cast vapor passages of limited cross-sectional area known in the art. In addition to the limitations on port location along a single straight-drilled vapor passage, the geometry of the fixed scroll structure imposes a practical limitation on the diameter of any holes that may be drilled through it. Adding additional volume and mass to the fixed scroll simply for the purpose of providing dimensions sufficient to the economizer vapor passages is not an optimal solution. Further, additional specialized machining is required to drill larger diameter vapor passages than for smaller passages, further adding to the cost of component fabrication.

By way of example and not limitation, implementations of these and other embodiments of the invention may include one or more of the features described elsewhere herein. These and other features and advantages of this invention will be more readily understood and appreciated by a person of ordinary skill in the art from the following detailed description of the various aspects of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Without limiting the invention to the features and embodiments depicted, certain aspects of this disclosure, including the preferred embodiment, are described in association with the appended figures in which;

FIG. 1 depicts the configuration of a first scroll compressor known in the art;

FIG. 2 depicts the configuration of a second scroll compressor known in the art;

FIG. 3 depicts the relationship between pressure and enthalpy in an exemplary economized vapor compression system;

FIG. 4 depicts the component arrangement in an exemplary economized vapor compression system;

FIG. 5 depicts drilled working fluid passage inlets typical of the known art scroll compressors depicted in FIGS. 1 and 2;

FIG. 6 depicts the inside (scroll side) of an exemplary prior art economized scroll compressor showing working fluid injection ports;

FIG. 7A depicts the outside surface of an exemplary prior art economized scroll compressor showing a cast working fluid passage and two elongated ports;

FIG. 7B depicts the inside (scroll side) of the exemplary prior art economized scroll compressor shown in FIG. 7A with two elongated ports from the working fluid injection ports;

FIG. 8 provides a semi-exploded solid model of a portion of one embodiment of the inventive system;

FIG. 9 provides a semi-exploded line drawing of a portion of one embodiment of the inventive system;

FIG. 10A depicts an alternate view of the internal working fluid flow path and the injection plate used with the inventive system;

FIG. 10B depicts an elevated view of said injection plate showing the relative position of the injection ports of the inventive system;

FIG. 11A depicts a cross-sectional view of a solid model showing the internal working fluid flow of one embodiment of the inventive system;

FIG. 11B depicts a cross-sectional view of a solid model showing the flow of working fluid through the injection ports and the intermediate pressure tap in one embodiment of the inventive system;

FIG. 12A depicts the upper (outer) side of the fixed scroll assembly of one embodiment of the inventive system comprising a circumferential injection plenum;

FIG. 12B depicts the scroll (inner) side of the fixed scroll assembly of one embodiment of the inventive system;

FIG. 13 depicts the upper (outer) side of the fixed scroll assembly of one embodiment of the inventive system;

FIG. 14A depicts a first position of the orbiting scroll with respect to the fixed scroll and economizer ports of one embodiment of the inventive system;

FIG. 14B depicts a second position of the orbiting scroll with respect to the fixed scroll and economizer ports of one embodiment of the inventive system;

FIG. 15 depicts the upper (outer) side of one embodiment of the inventive system depicting the economizer ports;

FIG. 16 provides a cross-sectional view of a solid model of the external working fluid injection path and injection plate of one embodiment of the inventive system;

FIG. 17 provides a cross-sectional line drawing of the external working fluid injection path and injection plate on one embodiment of the inventive system;

FIG. 18 depicts an upper view of a solid model of one embodiment of the inventive system comprising an external economizer injection feed configuration;

FIG. 19 depicts an upper view of one embodiment of the inventive system comprising an external economizer injection feed configuration; and

FIG. 20 depicts the relationship between the economizer port area and the displacement of the economized scroll compressors of two embodiments of the inventive system.

DETAILED DESCRIPTION OF SOME ASPECTS OF THE INVENTION

With reference to FIG. 4 and associated FIG. 3 depicting an exemplary economized vapor compression heat transfer system and the state of the working fluid circulating therein, flash tank or heat exchanger 404 is disposed between expansion valves 403 and 405 which are operative to set an intermediate pressure for the working fluid in the tank. This working fluid is effectively sub-cooled in tank 404, thereby reducing its enthalpy, and a predominantly vaporized portion of this intermediate-pressure working fluid is extracted and communicated to compressor 401 of this invention via injection flow valve 407.

In one embodiment, the working fluid in the economized vapor compression system comprises R-410A refrigerant. In one embodiment, the working fluid in the economized vapor compression system comprises R-404A refrigerant. However, a person of ordinary skill in the art will recognize that this disclosure envisions that the apparatus and associated methods of this invention may be used with any available or yet-to-be-developed suitable working fluid comprising refrigerant, another compound, or any mixture of working fluid(s) and compound(s) suitable for the intended purpose by adapting the features and elements taught herein to accommodate the particular characteristics of said working fluid. In other words, operation and patentability of the inventive system is independent of any particular working fluid(s) or combinations thereof.

FIGS. 8, 9, 10A, and 10B depict different views of several embodiments of the fixed scroll assembly with associated and adjacent components. Compressor 401 receives the intermediate-pressure working fluid via one or more external economizer port inlet(s) 801 disposed on the compressor. The working fluid received at the economizer port inlet 801 is communicated to the injection plenum comprising a volume bounded by, in combination, channel 804 comprising one or more injection port(s) 802 machined into the outer (non-scroll) surface of the fixed scroll assembly, one or more sealing gaskets 805A and 805B of any preferred configuration, and injection plenum sealing plate 806 via non-linear working fluid channel 807. Injection port(s) 802 allow working fluid to pass from the volume of the injection plenum into first pockets of the scroll compressor. Intermediate pressure tap 803 permits higher pressure, partially compressed working fluid to pass from a second pocket into the back compartment of the scroll compressor, external to the injection plenum and floating seal plate 808. FIGS. 8, 9, and 10B show injection ports 802 disposed on an approximate circumferential locus parallel to the curved wall of the scroll wrap disposed on the opposite side of the plate through which said injection ports pass. This arrangement allows each of the injection ports to simultaneously provide the same effective area through which working fluid vapor may pass, each simultaneously ranging from fully open to fully occluded depending on the position of the orbiting scroll wrap with respect to the fixed scroll wrap and the ports. This multi-port configuration, with the flexibility to locate the ports in a locus corresponding to the curvature of the scroll wraps at any position within the surface area of injection plenum channel 804, is a novel improvement over prior art devices where a port comprising a single hole is generally limited in cross-sectional area to the thickness of the scroll wrap wall, which in turn limits the mass flow of economizing vapor and the effectiveness of the economization process. In one embodiment, one or more injection ports are shown to undercut the scroll wrap wall at 1001, providing additional injection port placement and sizing options for optimized economization.

FIGS. 11A and 11B present magnified views of reduced-element solid models depicting only certain elements described above. The flow of working fluid from economizer inlet port 801 is shown to flow through non-linear working fluid channel 807 into the injection plenum underneath injection plenum sealing plate 806. Notably, intermediate pressure tap 803 can be seen to be external to the injection plenum enclosed by injection plenum sealing plate 806. This is essential to achieve the pressure differential required to support floating seal plate 808. While the pressure of the working fluid injected at inlet 801 is properly classified as being of intermediate pressure, Applicants' invention utilizes an independent intermediate pressure differential within the economized compressor created by a novel system of working fluid flow and partial compression. As shown in FIG. 11A and described previously, working fluid is communicated from inlet 801 to the injection plenum at a first intermediate pressure. Subsequently, working fluid is communicated from the injection plenum into pockets of the compressor via the one or more injection port(s) 802. The rotation of the orbiting scroll with respect to the fixed scroll, depicted and described elsewhere herein, compresses the working fluid and provides a small portion of partially-compressed working fluid from a pocket within the scroll at a second intermediate pressure greater than the first intermediate pressure, via intermediate pressure tap 803, to the back compartment of the compressor external to floating seal plate 808. This use of partially re-pressurized working fluid at a second intermediate pressure enables floating seal plate 808 to remain in place and provide the necessary axial stability for the orbiting scroll without imposing additional stress via fixed mechanical connection that would introduce additional maintenance requirements and decrease reliability.

FIGS. 12A and 12B depict the upper (fixed) scroll of one embodiment of the inventive apparatus. In FIG. 12A, the upper surface of the fixed scroll is shown with injection ports 802, intermediate pressure tap 803, and circumferential injection plenum working fluid inlet 1201. FIG. 12B shows the same injection ports 802 and intermediate pressure tap 803 from that reverse perspective along with scroll wrap 1202 which is not visible from the other side. FIG. 13 comprises an image of an actual fixed scroll assembly corresponding to the drawing of FIG. 12A with a slightly different orientation.

Typically, injection ports will be configured in closely-spaced groups or sets, each set comprising more than one port disposed on the fixed scroll at points of equal pressure during scroll operation. In one embodiment, the injection ports will generally be equidistant from the center or rotation of the orbiting scroll on a line passing through said center of rotation. The number of injection ports, their shape(s), cross-sectional area(s), and locations are parameters selectable by designers to meet design criteria for a particular system or application. Any combination of these parameters are envisioned by this disclosure.

The position of the economized injection ports with respect to both the fixed and orbiting scrolls is critical to proper operation given the complex relative motion of two asymmetric scroll structures and the requirement for properly timed working fluid injection during the compression process. FIGS. 14A and 14B show the necessary relationship between the injection ports and the fixed and orbiting scrolls in two distinct relative positions. In the embodiment of FIG. 14A, the entire apertures of two sets of four injection ports are located at points of equal pressure on both sides of the fixed scroll 1401 and are blocked (closed) by the position of the orbiting scroll 1402 so that no working fluid may be injected into the scroll. Full blockage requires that the diameter of each hole be at least slightly less than the thickness of the wrap of the orbiting scroll. First relative scroll position 1403 corresponds to the point in the compression cycle immediately before the intermediate pocket between scroll wraps begins to experience compression. FIG. 14B depicts a second relative scroll position after approximately one-sixth of a full rotation (60°) of the orbiting scroll. At this second relative position 1404, the injection ports can now be seen to be largely unblocked (open) permitting intermediate-pressure working fluid to pass into the scroll for economized operation.

In one embodiment, the diameter of the injection ports may be slightly greater than the wrap thickness of the scroll when the ports slightly undercut the scroll wraps.

Because the scroll wraps are circular with a radius from the center that varies as a function of angular position, it can be appreciated that locating the injection ports along a straight line (as constrained by the known art method of straight holes drilled into the fixed scroll base) would not allow the injection ports to perfectly align with the curvature of the orbiting scroll wrap as it moves about its axis of rotation. However, the circumferential injection plenum of Applicants' invention easily permits the centers or circumferences of circular injections ports to describe an arc with a constant radius, an arc with a radius dependent upon angular position, or any other desired non-linear path to either match or complement the curvature of the orbiting scroll, or any other straight, curved, or other geometrical configuration desired. While circular injection ports are generally preferable due to the relative ease of drilling or machining round holes, in some embodiments the injection ports may comprise one or more non-circular opening(s) between the scroll pockets and the injection plenum. Such non-circular port(s) may be in the shape of a rectangle with straight or curved sides, an ellipse with a straight or curved major or minor axis, a crescent, or any other preferred shape. Further, the size and shape of each of more than one injection ports may be independently selected to optimize compressor operation. This is a principal improvement of injection plenum of the inventive system over all known art that employs linearly drilled or cast vapor passages.

FIG. 15 depicts the upper structure of a fixed scroll, including two sets of refrigeration injection ports 1501 disposed within a circumferential injection plenum, in one embodiment of the invention suitable for use with one or more external working fluid conduits or tubes. FIGS. 16 and 17 provide cross-sectional views of a solid model and line drawing, respectively, of an embodiment showing injection conduits or tubes 1601 communicating working fluid from inlet 801 directly to injection plenum sealing plate 1602 through the upper surface rather than through the lower surface of the plenum. As noted elsewhere, this configuration enables the use of higher mass flow rates than is possible via internal flow channels of other embodiments presented herein. The number of conduits or tubes, the diameter(s) of those tubes or conduits, and any angular variations or bends that may be necessary to properly communicate the working fluid may be varied as necessary to achieve an appropriate working fluid flow with the volume and pressure necessary for optimized economized operation.

FIGS. 18 and 19 depict a solid model and a cut-away version of an actual prototype, respectively, of separate embodiments of the inventive system comprising external working fluid feed tubes or conduits described above and in FIGS. 16 and 17. It can be seen that the injection conduits or tubes 1601 are disposed between the scroll compressor structure and a protective outer casing wherein said full (not cut-away) production casing would provide physical protection to the tubes or conduits and at least partial confinement of any vaporized working fluid that may be released in the event of catastrophic failure of the economized working fluid feed system.

In one embodiment, the economizer input port 801 and external working fluid feed tubes 1601 are fabricated at least in part from metal, including but not limited to steel, copper, iron, aluminum, or any other metallic material or alloy. In one embodiment, all or part of economizer input port 801 and/or the external working fluid feed tubes, connectors, or supports may comprise at least a portion of plastic, plasticized, rubber, rubberized, composite, synthetic, or other non-metallic materials suitable for the intended purpose. Advantages of non-metallic tubes, conduits, connectors, or supports include but are not necessarily limited to their ability to resist corrosion or deterioration under certain operating or environmental conditions, absorb a degree of vibrational or mechanical stress due to some degree of inherent flexibility, and provide for simplified installation and field maintenance. Any materials best suited for a particular use within a particular vapor compression system are envisioned by the scope of this disclosure.

The parameters of operation of an economized vapor compression heat transfer system are governed by many factors, including but not limited to required system capacity, compressor displacement and pressure ratio, required or available compressor driving power, working fluid type, and evaporator and condenser performance with respect to the environmental conditions to which they are subjected. As the heart of the system, the compressor should be optimally configured to provide maximum cooling or heating capacity for a given cost of fabrication and operation of the system. For example, in one embodiment an optimized system will achieve the greatest capacity per kWe of driving power.

The compressor apparatus disclosed herein provides novel structure to flexibly achieve optimization of economized vapor compression refrigeration systems, including large capacity systems not practicable with known technology, and therefore represents an improvement in the art. Reduction to actual practice has revealed that embodiments of the apparatus disclosed herein are particularly well-suited as envisioned and provide superior configurability.

As noted above, vapor compression heat transfer systems may be configured to function as either cooling or heating systems. The particular working fluid(s) used in these systems may be selected to optimize performance in either mode or may be selected to meet certain acceptable performance criteria in both modes with certain compromises in either or both modes, depending upon the particular application. The mass flow rate of injected intermediate-pressure working fluid necessary to provide fully economized operation varies greatly with compressor displacement, working fluid type, and the range of system operation defined by the compressor's saturated suction temperature, or SST, and saturated discharge temperature, or SDT.

As a general rule, smaller displacement compressors require a smaller port area than are necessary for larger displacement compressors. However, ports with certain dimensions may be suitable for a wide range of displacements so this general rule does not universally imply that an increase in compressor displacement requires a greater total port area. Also, low temperature systems suitable for refrigeration purposes (including sub-zero temperature capability) generally require a lower economized mass flow rate than do refrigeration systems operating at higher temperatures, such as air conditioning systems. In turn, the total effective port area and the cross-sectional area of intermediate pressure working fluid feed tubes or conduits necessary to enable sufficient but not excessive mass flow rates also varies as a function of compressor displacement.

FIG. 20 presents the generalized relationship between the economized port area as a function of compressor displacement for two embodiments comprising elements disclosed herein. Curve 2001 represents this relationship for a series of economized scroll compressors configured with one or more internal vapor channels as depicted in FIGS. 8-11 and described in detail above. It can be seen that as compressor displacement increases, the optimized value of total injection port area (the sum of the cross-sectional areas of all ports) expressed as a percentage of the compressor's displacement volume decreases. Similarly, curve 2002 shows an embodiment of economized scroll compressors with external working fluid injection tubes or conduits as depicted in FIGS. 16-19 and reveals that the optimized port area of these larger compressors also decreases as displacement increases but at a significantly lesser rate. A significant factor in this difference is the configurability afforded by the use of external refrigeration injection tubes or channels. Where smaller compressors can perform acceptably with one or more fixed dimensions vapor passages internal to the fixed scroll (see, for example, FIG. 11A), the number and cross-sectional area of larger external working fluid injection tubes or conduits may be varied to better accommodate the increased mass flow rates. However, the performance of both internal and external vapor feed systems is enhanced by the greater configurability of injection port size and location due to the Applicants' novel injection plenum.

Typical mass flow rates for various sizes of economized scroll compressors of the embodiments described herein are summarized in Table 1.

TABLE 1 Compressor Capacity and Associated Mass Flow Rates (Example using R-410A refrigerant as working fluid; mass flow data in lbm/hr)) Operating Relative Displacement (in³/rev) Condition Mass Internal Feed Displacements External Feed Displacements (SST/SDT) Flow Rate 6.93 7.78 8.69 10.25 13.18 16.93 21.67 23.70 27.08 −25°/105° F. Low 173 185 199 217 248 381 466 487 580  −4°/140° F. Medium 339 362 384 417 469 735 895 936 1116  60°/140° F. High 523 566 604 656 717 1146 1373 1438 1721

Data point 2003 of FIG. 20 represents the operational point of an economized scroll compressor known in the art. The port area expressed as a function of compressor displacement is observed to be approximately half of the area of those in the inventive external feed system 2002 suited for larger capacity operation. Both the type of working fluid and the temperature operating range of this known art economized compressor contribute to the need for a smaller port area, but such port area will necessarily increase for larger capacity systems employing larger displacement compressors. It is believed that the smaller port area of the known art system is a significant contributing factor as to why this design, based on the known art, has not proven to be capable of functioning in larger displacement, higher performance systems with greater mass flow rates and generally larger injection port areas. Applicants' inventive system overcomes this limitation of the known art.

Any number of methods of operation of the apparatus described herein are envisioned by this disclosure. For example, and without limitation, a method of operating an economized scroll compressor with a circumferential injection plenum would comprise calculating and providing a certain mass flow of working fluid at a specified pressure to the economizer input such that sufficient enthalpy reduction is achieved via working fluid injection through the injection plenum, that sufficient pressure is achieved in the back chamber to provide mechanical stability for the orbiting scroll, and that maximum heat transfer capacity is achieved per unit of displacement volume. Similarly, a method of fabrication is enabled herein where injection ports are configured to communicate reduced enthalpy working fluid from an economized input to the scroll pocket(s) via an injection plenum according to the instant disclosure.

While the foregoing disclosure sets forth various exemplary embodiments using specific drawings and descriptions, one or more of said embodiments or other embodiments described in the preceding paragraph may be achieved by other means or functions evident to persons of ordinary skill in the art and are thereby also contemplated by the instant disclosure. Applicant's disclosure in its written description and claims must be considered in its entirety for all it teaches and claims and not as a series of disparate and unrelated pieces. Certain elements of this invention may be independently operable but may not be properly separated from the invention as a whole for purposes of determining patentability. For example, combinations of known elements to achieve a system or method previously unknown in the art would, by definition, comprise a novel invention for purposes of patentability and would further comprise “significantly more” than the simple use of known elements to achieve predictable results. Reduction of Applicant's invention to disparate elements in an attempt to deem said invention as obvious over known art without appreciation for the novelty of the combination of said elements would fail to appreciate the invention as a whole.

With respect to methods and processes, it will be recognized by persons of ordinary skill in the art that certain of the steps in said methods or processes are not necessarily required to be performed in the order taught by Applicant's recitation. When process or method steps may be performed in an alternative order such that the results achieved by said process or method are equivalent to those taught by Applicant, such alternate order of performance are envisioned by the scope of this disclosure. A person of ordinary skill in the art will appreciate the extent to which one or more step(s) of any process or method taught or claimed herein must necessarily precede another, but in all other instances, the scope of Applicant's disclosure should be viewed as inclusive of the family of processes or methods comprising equivalent steps that achieve the results taught and claimed by Applicant's process and method steps in any order of performance. Further, certain process or method steps may not be required for one or more embodiments, and such embodiments also fall within the scope of this disclosure.

Unless otherwise noted herein, the descriptive articles “a” or “an,” as used in the specification and claims are to be construed as meaning “at least one of”. Thus, for example, recitation of combinations of elements such as “at least one of any of A, B, and C” describes any manner of combination of said elements, including combinations comprising A, B, C, A and B, A and C, B and C, or A and B and C.

Further, whenever the singular form of an object is used or implied, the use of the plural is understood to be included, and vice versa. For example, the term “input ” may refer to one or more than one such element. Terms denoting one or more, such as “input(s)”, are used herein for grammatical propriety where deemed applicable and are not to be distinguished from usage where only the singular or plural are used unless expressly stated otherwise.

Applicant has described its invention in the context of certain embodiments, some preferred over others in certain instances, for certain purposes, or both. The scope of this disclosure is intended to encompass all embodiments related to the disclosed subject matter and for all useful purposes to which said embodiments may be applied. The exemplary embodiments listed herein are provided to be enabling rather than limiting, as persons of ordinary skill in a great variety of arts will immediately recognize how the apparatus, systems, and methods disclosed herein may readily be applied to aspects of their arts, and such applications are therefore additionally enabled by Applicant's disclosure and therefore fall within its scope. Certain elements of Applicants' disclosure may be preferentially combined with other elements to provide specific functionality. Likewise, certain elements of Applicants' disclosure may be omitted in certain embodiments when specific functionality provided by those elements is neither useful nor desired. In other words, any combination of the elements disclosed herein deemed to be the most practicable for any intended purpose may be employed without limitation, and each of said combinations are deemed to be within the scope of this disclosure. 

What is claimed is:
 1. An economized scroll compressor for use with a working fluid and a source of rotational mechanical power, said compressor comprising: A. a fixed scroll assembly comprising: (i) a fixed planar base; (ii) a first scroll wrap with wrap walls disposed perpendicular to a first surface of said fixed planar base; (iii) a circumferential working fluid vapor injection plenum bounded in part by a second surface of said fixed planar base; and (iv) one or more working fluid vapor injection ports configured to allow working fluid vapor communication from said working fluid vapor injection plenum to pass through said fixed planar base to the region bounded in part by said second surface of the fixed planar base; and B. an orbiting scroll assembly: (i) comprising an orbiting planar base comprising a second scroll wrap with wrap walls disposed perpendicular to said orbiting planar base; (ii) disposed such that said second scroll wrap is intermeshed with said first scroll wrap, thereby forming one or more pockets between the walls of the first and second scroll wraps; and (iii) in rotational power receiving communication with said source of rotational mechanical power.
 2. The economized scroll compressor of claim 1 wherein said working fluid comprises a refrigerant.
 3. The economized scroll compressor of claim 2 wherein said refrigerant comprises at least one of any of R-410A refrigerant and R-404A refrigerant.
 4. The economized scroll compressor of claim 1 wherein said circumferential working fluid vapor injection plenum comprises a volume bounded by a channel machined into said second surface of said fixed planar base, one or more sealing gasket(s), and an injection plenum sealing plate.
 5. The economized scroll compressor of claim 1 wherein said circumferential working fluid vapor injection plenum is in working fluid vapor receiving communication with an economizer port inlet via at least one of any of a working fluid channel and a working fluid conduit or tube.
 6. The economized scroll compressor of claim 5 wherein said working fluid conduit or tube is comprised in whole or in part of at least one of any of steel, copper, iron, aluminum, alloy, plastic, plasticized material, rubber, rubberized material, composite material, or synthetic material.
 7. The economized scroll compressor of claim 1 wherein said working fluid vapor injection ports comprise two or more sets of one or more ports each, wherein said ports comprise at least one of any of circular ports, rectangular ports with straight or curved sides, elliptical ports with straight or curved major or minor axes, or crescent-shaped ports.
 8. The economized scroll compressor of claim 7 wherein each of said two or more sets of working fluid vapor injection ports are disposed at positions of equal pressure during compressor operation.
 9. The economized scroll compressor of claim 7 wherein each of said one or more working fluid vapor injection ports in each of said one or more sets are disposed on an arc that corresponds to the arc of an adjacent fixed scroll wrap wall.
 10. The economized scroll compressor of claim 1 further comprising: A. an intermediate pressure tap from a pocket within the scroll at a higher working fluid vapor pressure than that present within the injection plenum, and B. a floating seal plate disposed atop said circumferential working fluid vapor injection plenum and within a sealed back chamber, said chamber pressurized by working fluid vapor communicated via said intermediate pressure tap so as to maintain the position of said floating seal plate against said injection plenum.
 11. A economized vapor compression refrigeration system utilizing a working fluid, the system comprising: A. a first heat exchanger configured to transfer heat energy to the working fluid; B. a scroll compressor in heated working fluid receiving communication with said first heat exchanger, said compressor comprising: (i) a fixed scroll assembly comprising: (a) a fixed planar base; (b) a first scroll wrap with wrap walls disposed perpendicular to a first surface of said fixed planar base; (c) a circumferential working fluid vapor injection plenum bounded in part by a second surface of said fixed planar base; and (d) one or more working fluid vapor injection ports configured to allow working fluid vapor communication from said working fluid vapor injection plenum to pass through said fixed planar base to the region bounded in part by said second surface of the fixed planar base; and (ii) an orbiting scroll assembly: (a) comprising an orbiting planar base comprising a second scroll wrap with wrap walls disposed perpendicular to said orbiting planar base; and (b) disposed such that said second scroll wrap is intermeshed with said first scroll wrap, thereby forming one or more pockets between the walls of the first and second scroll wraps; C. a second heat exchanger in compressed heated working fluid receiving communication with said scroll compressor, said second heat exchanger configured to remove heat energy from said working fluid at a constant pressure; D. a first expansion valve in working fluid receiving communication with said second heat exchanger, said first expansion valve configured to reduce the pressure in the working fluid to an intermediate pressure; E. A working fluid flash tank or heat exchanger in intermediate pressure working fluid receiving communication with said first expansion valve; F. a working fluid vapor injection valve in intermediate pressure working fluid vapor receiving communication with said working fluid flash tank or heat exchanger and in intermediate pressure working fluid vapor sending communication with said circumferential working fluid vapor injection plenum; and G. a second expansion valve in intermediate pressure working fluid receiving communication with said working fluid flash tank or heat exchanger and in expanded working fluid sending communication with said first heat exchanger; wherein the operation of said scroll compressor is optimized via injection of said intermediate pressure working fluid vapor from said circumferential working fluid vapor injection plenum into pockets formed by the intermeshed walls of said first and second scroll wraps via said one or more working fluid vapor injection ports.
 12. The system of claim 11 wherein said working fluid comprises at least one of any of R-410A refrigerant and R-404A refrigerant.
 13. The system of claim 11 wherein said working fluid vapor injection ports comprise two or more sets of one or more working fluid vapor injection ports each, wherein said ports comprise at least one of any of circular ports, rectangular ports with straight or curved sides, elliptical ports with straight or curved major or minor axes, or crescent-shaped ports.
 14. The system of claim 13 wherein each of said two or sets of working fluid vapor injection ports are disposed at positions of equal pressure during compressor operation.
 15. The system of claim 13 wherein each of said one or more working fluid vapor injection ports in each of said one or more sets are disposed on an arc that corresponds to the arc of an adjacent fixed scroll wrap wall.
 16. The system of claim 11 wherein said circumferential working fluid vapor injection plenum comprises a volume bounded by a channel machined into said second surface of said fixed planar base, one or more sealing gasket(s), and an injection plenum sealing plate.
 17. A method of providing economized operation of a working fluid scroll compressor comprising a fixed scroll wrap and an intermeshed orbiting scroll wrap, the method comprising steps of: A. providing a circumferential working fluid vapor injection plenum comprising an intermediate pressure working fluid vapor inlet; B. providing one or more working fluid vapor injection ports, each said port configured to communicate intermediate pressure working fluid vapor from said working fluid vapor injection plenum to one or more pockets formed by an intermeshed fixed scroll and orbiting scroll; and C. injecting said intermediate pressure working fluid vapor into said pockets so as to reduce the enthalpy of the working fluid during compression of the working fluid vapor.
 18. The method of claim 17 wherein said one or more working fluid vapor injection ports comprise two or more sets of one or more ports each, wherein each of said ports comprise at least one of any of circular ports, rectangular ports with straight or curved sides, elliptical ports with straight or curved major or minor axes, or crescent-shaped ports.
 19. The method of claim 18 wherein each of said working fluid vapor injection ports are disposed at positions of equal pressure during compressor operation.
 20. The method of claim 18 wherein each of said two or more sets of one or more working fluid vapor injection ports are disposed on an arc that corresponds to the arc of an adjacent fixed scroll wrap wall. 